Motor as Load

Induction Generator

Dueling Banjos!

Why?

"Give me some links & papers on this"

Now try saying please. This site is not information on demand!

Tony, I agree that the tone seems kind of abrupt, but I also understand that the OP MIGHT not be fluent in english and may not be dressing up his post with the proper niceties due to non-fluency with the language, so I'll give him a pass on that.... this time....

Let this be your Payfver. Cool!!!

Permanent magnet DC motors connected to large resistor banks work real well as a mechanical load. field coil DC motors can work too if you have a voltage source to power the field winding and you can vary the field voltage to change the load, or you can vary the load resistance or both. doing the same with an AC induction motor is a bit more complex. DC motors for loads are dead easy. what you are doing is turning the DC motor into a DC generator and forcing the resultant generated power to be dissipated into a resistive load. by changing the field winding voltage, you can control the voltage generated by the motor as well.

When I worked for a company that designed and manufactured motor inverters (aka ac motor drives), we would test the inverters by connecting two induction motors back to back. The two inverters were set to run at the same speed. Load was applied by lowering the speed of the load inverter until the proper loading condition was achieved. The load inverter put power back into the 480vac power lines which fed the drive inverter. We were able to operate 400 hp systems for extended periods of time without running up the electric bill.

Oh no, not again. This is a warning. Do not attempt to reply to the Snave reply, as I'm sure there are at least 5000 replies addressing his attempt to create a 400HP drive that does not consume power.

you beat me to it!!!!

PFR & 666 -You two guys have got to be kidding. Our test rig was not a perpetual motion machine. The 400hp motor drive test consumed about 80 hp of energy as each motor drive was about 90% efficient.

Your configuration did not enable you to run the test bed without using additional electrical power, as you implied, that's all. If you are telling us now that you used 80HP to run the test bed, so be it.

Hi

I have not seen any specific papers on this, but I have a setup using a control Techniques SP drive to drive the motor, with a second drive connected as an active front end. The advantage of this system is that you can load the "test" motor with the second motor and any power that you pull out of the test motor, can be fed back into the supply minus the losses in the motor and inverters.

Any active front end drive could be used for this.

I operate the drive in torque mode so that I can control the load on the motor by adjusting the torque. Setting the set point speed above synchronous speed will cause the motor to overspeed and can be used to test the braking effect. Setting the target speed below synchronous speed will pull power out of the test motor.

The onboard PLC on the SP drive can be used to create a torque speed profile to simulate real loads if you are testing soft starters.

Best regards,

Mark Empson.

http://www.vfd-emc.co.nz